The genotype combination with the highest PFS benefit correlated with an OS improvement will be chosen for further analyses. The difference in PFS between favourable genetic profiles and the unfavourable genetic profiles will be assessed with the log-rank test and the Kaplan-Meier method to evaluate survival curves. A Cox proportional hazards model, with the possible genetic profiles and the clinical and pathological patient characteristics individually correlated with the PFS, will be used to calculate the adjusted hazards ratio (HR) and the 95% confidence interval (95% CI). A P value of <0.05 will be accepted as statistically significant. The Kaplan-Meier and Cox proportional hazards analyses will be performed using the SPSS version 17.0 (SPSS, Chicago, IL).